Table 4 Learning points

Pseudolesions: Very common. Know-them to recognize them

Meningioma and hemangioma can simulate aggressive periosteal reaction

Meningioma: Calcification, dural tail, intense enhancement, hyperostosis. Beware of variable bone involvement. 1H-MRS: Alanine (specific)

Hemangioma: Expansile, trabeculated, spoke-wheel pattern, fatty content.

Epidermal inclusion cyst: Previous injury, DWI restriction

Dermoid cyst: DWI restriction, fatty content

Fibrous dysplasia: Young patient. “Ground-glass” matrix virtually pathognomonic. Possible predominant lytic-cystic component in calvarium

Eosinophilic granuloma: Young patient with focal lytic lesion with “button sequestrum”

Giant-cell tumor: Hypervascular bone expansion lesion with flow-voids

Aneurysmal bone-cyst: Bone-expanding lesion with fluid hemosiderin levels. May be secondary if prominent solid components

Myeloma/metastastasis: Elderly patients with multiple lesions

Blastic metastasis: Prostate, breast, transitional cell, neuroendocrine, PNET, lymphoma

Hypervascular metastasis: thyroid, renal, hepatocarcinoma, neuroendocrine and melanoma

Transdiploic or aggressive single lesion: Differential of plasmacytoma, metastasis, lymphoma or meningeal lesion (meningioma/ SFT). Functional imaging can be useful in narrowing differential